Wind Farms can produce up to 5 percent more power

Thursday November 14, 2013 15:53

ECN’s Active Wake Control increases output and reduces maintenance

The Active Wake Control system of the Energy research Centre of the Netherlands (ECN) is able to increase the electricity production of wind farms by 0.5 to 5 per cent. Additionally, it is expected that maintenance costs can be reduced with 3 per cent. The technology has been tested on 5 wind turbines at ECN’s wind farm test site and the next step is to test the technology at an offshore wind farm, to prove the benefits on a larger scale.

Through optimal positioning of the wind turbines, the patented system reduces the wake effects of turbulence. In a perfect line position, turbines produce 100 percent power, but also take a 100 per cent load on axes and blades. When placed behind each other, the upstream turbine still produces 100 percent power, but the capacity of the downstream turbines is reduced to 60 or 50 percent. On top of this, wake effects caused by turbulence increase their load to 110 or 115 per cent and maintenance costs rise proportionally.

By changing the pitch angle and/or the yaw angle of the front turbine a few degrees, the turbulence is deflected/altered, thus reducing the load and increasing the power production of downstream turbines.

“This is a solution to substantially increase the production of the whole wind farm, while also reducing the load and maintenance costs,” Haico van der Heijden of ECN explains.

ECN first used in-house developed simulation tools to test the principle of “Active Wake Control”, but did a full-scale test on five 2.5 Megawatt Nordex turbines and finally on scaled wind farm with ten 10KW turbines at its test site in the Wieringermeer in the Netherlands. All tests showed the same result: the wind farm’s power production was increased by 0.5 to 5 percent and the loads were significantly reduced.

ECN is world leader in R&D of offshore wind farms, constantly working on technologies to improve efficiency and maximise energy production. The principle of Active Wake Control was first presented during the Dutch Wind R&D Workshops, attended by experts from all over the world. After a period of testing and improving, the tool is now ready to be applied on a large scale.

“The next step is a large wind farm, preferably offshore. That is not a place where you want to experiment, which is why we have waited until the technique had proven itself,” says Van der Heijden.